1. Field of the Invention
The present invention relates to a flexible cover, more specifically, to an omnidirectional bellows for shielding reciprocally displacing mechanisms, in order to protect such mechanisms from extrinsic factors such as for example dust, dirt, light, moisture, humidity, etc.
2. Description of the Prior Art
Conventional bellows used for reciprocally displacing mechanisms have been assembled into a size and shape to have uniform gap between inner border of bellows ends and surface of a guide-rail so as to be allowed to smoothly repeat reciprocal displacement along with the guide-rail.
When the reciprocal displacement mechanisms having gap incorporated between the guide-rail and the bellows moves relatively long distance, the midsection of bellows is relaxed (sagged) in the direction of gravity while reciprocally displacing, so that there may occur cases in which the inner surface of bellows may contact with the guide-rail or the outer surface thereof in the direction of gravity may impinges against other devices to eventually cause disadvantages such as breakage.
In order to avoid sagging midsection of bellows, it is well known in the art that guide-plates in the form corresponding to the cross-sectional profile of the guide-rail used may be interposed every six (6) through seven (7) fold. The guide plates may be usually made of hard vinyl chloride plate die-cut by a press, in a form that the inner border approximates to the guide-rail surface with no gap, and aluminum frame is fit onto the outer border as reinforcement.
As long as the reciprocally displacing mechanism covered by the bellows of the prior art is used in lateral position and under circumstances of relatively fewer vibrations, such conventional structure may withstand well. However if the reciprocal displacement is used not only in horizontal but also in vertical, inclined, reversed, and altering direction, or is used under intensive vibrations, for example in case of aircrafts or express trains, the guide plate will act as weight to strain the bellows in gravity direction to cause disproportional stretching, or the midsection between the guide plates attached every six through seven fold may sag in gravity direction to cause impingement against other devices surrounding the bellows, difficulty in smooth stretching, or breakage.